Agrochemical formulations are generally designed based on customer needs and the physiochemical properties of the active ingredients, for example, the solubility of the active ingredient in water or non-aqueous solvents. There are two major categories of formulations, solid formulations and liquid formulations.
Emulsifiable concentrates (EC) containing agricultural active ingredients, represent one class of liquid formulations that are routinely used to control weeds and pests in agriculture. Active ingredients, in the form of solids or liquids, may be formulated as emulsifiable concentrates and include insecticides, herbicides, fungicides and nematicides. EC formulations may contain, in addition to the dissolved active ingredient, a water immiscible solvent, one or more surfactants, an adjuvant and other inert ingredients. The EC may be diluted with a carrier solvent such as water at the point of use for spray application to control pests or weeds or may be applied directly to the area of interest, such as for example, to water flooded paddy rice.
Adjuvants are important components of EC formulations and are defined as substances which can increase the biological activity of the active ingredient, but are themselves not significantly biologically active. Adjuvants assist with the effectiveness of the active ingredient such as, for example, by improving the delivery and uptake of an herbicide into a target weed plant leading to improved biological control.
Adjuvants, in the form of solids or liquids, can be added directly to a formulated agricultural product, such as an EC, to provide improved performance of the product upon application. Commonly used adjuvants may include, for example, surfactants, spreaders, petroleum and plant derived oils and solvents, and wetting agents. Examples of commonly used adjuvants include, but are not limited to, paraffin oil, horticultural spray oils (e.g., summer oil), methylated rape seed oil, methylated soybean oil, highly refined vegetable oil and the like, polyol fatty acid esters, polyethoxylated esters, ethoxylated alcohols, alkyl polysaccharides and blends, amine ethoxylates, sorbitan fatty acid ester ethoxylates, polyethylene glycol esters, organosilicone based surfactants, ethylene vinyl acetate terpolymers, ethoxylated alkyl aryl phosphate esters and the like. These and other adjuvants are described in the “Compendium of Herbicide Adjuvants, 9th Edition,” edited by Bryan Young, Dept. of Plant, Soil and Agricultural Systems, Southern Illinois University MC-4415, 1205 Lincoln Drive, Carbondale, Ill. 62901.
The term “built-in adjuvant” refers to one or more adjuvants that have been added to a particular formulation, such as a liquid or granule formulation, at the manufacturing stage of the product, rather than at the point of use of the product such as, for example, to a spray solution. The use of built-in adjuvants simplifies the use of agrochemical products for the end-user by reducing the number of ingredients that must be individually measured and applied.
Rice is an important cereal crop grown in many parts of the world and is cultivated under both wet and dry conditions. Control of noxious weeds in rice is very important in order to maintain high levels of agricultural productivity. Use of herbicide emulsifiable concentrates for weed control in flooded paddy rice is a very common agronomic practice in many rice growing regions. New herbicide products that offer improved performance relative to current products are in constant demand.
Cyhalofop-butyl, (2R)-2-[4-(4-cyano-2-fluorophenoxy)phenoxy]propanoic acid (CAS #122008-78-0), is a member of the aryloxyphenoxypropionic acid class of herbicides which are known in the art as the fop herbicides and is used to control grass weeds in rice. Cyhalofop-butyl is marketed as Clincher® herbicide (registered trademark of Dow AgroSciences LLC) and is sold in granule (GR), oil in water (EW) and emulsifiable concentrate (EC) formulations and exhibits good selectivity to rice when used in both dry land and flooded paddy applications.
Existing commercial EC formulations containing cyhalofop-butyl also contain relatively large amounts of petroleum derived solvents that serve primarily to dissolve the active ingredient. The solvent may contribute greater than 50 percent by weight (wt %) of the total formulation in currently marketed EC products containing cyhalofop-butyl. The use of petroleum derived solvents in these products can limit the biological performance of cyhalofop-butyl herbicide due to a minimal herbicidal adjuvant effect. Petroleum derived solvents may also present safety and handling issues due to their flammability and toxicity.
The present invention provides an improvement to EC herbicide products containing grass-active herbicides by the use of the relatively safer non-petroleum derived built-in adjuvants. Such EC compositions offer improved herbicidal efficacy on weeds in flooded paddy rice applications and improved safety to the applicator and the environment.